Gas burner



22, 1968 E. E. HIRSCHBERG ET AL 3,407,024 GAS BURNER Filed Dec. 23, 1966 rig! MV-ESNT orqw 5 rwin 8. -(iru'chber'g Cdwqr- 6. 7710 r v United States Patent 3,407,024 GAS BURNER Erwin E. Hirschherg and Edward E. Moore, Rockford, Ill., assignors to Eclipse Fuel Engineering Co., Rockford, Ill., a corporation of Illinois Filed Dec. 23, 1966, Ser. No. 604,218 3 Claims. (Cl. 431328) This invention relates to gas burners of the so-called infra-red type in which a gas-air mixture delivered to the back of a porous face plate flows through narrow passages extending transversely through the plate, and burns at the outer exposed face thereof. The periphery of the plate is usually seated on a shoulder within a flange at the side of a hollow casing covered by the plate and supplied with gas from a pressure source.

The primary object is to provide between the face plate and its supporting casing a novel seal which remains gas-tight in spite of the diflerential thermal expansion between the plate and easing that occurs in service operation of the burner.

A more detailed object is to interpose between the back of the face plate and its supporting shoulder a gasket ring of material which will accommodate a limited amount of relative edgewise shifting between the back of the face plate and the casing shoulder while maintaining a gas-tight seal.

Another object is to maintain the effectiveness of the seal ring under all service conditions by interlocking the peripheries of the face plate and easing through a refractory filling of wedge shaped cross-section.

The invention also resides in the novel mounting and composition of the seal ring and the interlocking filling.

Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings, in which FIGURE 1 is a side view of a gas burner embodying the present invention and broken away in diametrical section.

FIG. 2 is an exploded perspective view of the burner face and its mounting.

FIG. 3 is an enlarged section of a part of FIG. 1.

In the drawings, the invention is shown incorporated in a burner head comprising two flat and relatively thin perforated plates 11 arranged end to end .and covering the open side of a casing 12 which defines behind the plates a chamber 13 to which an air-gas mixture is supplied under pressure from a supply passage 14. The casing is clamped against .a wall 15 of the passage by a screw 16 which herein is made tubular and apertured at 17 and 18 for conducting gas from the passage to the chamber 13.

The edge portion of each plate 11 is seated in a recess within a peripherally continuous flange 19 corresponding in size and shape to but slightly larger than the plate. Spaced below the edge of the flange and extending around the inner wall 20 thereof is a flat, narrow and peripherally continuous shoulder 2.1 which forms a backing for the plate.

For infra-red burners, each face plate is composed of porous heat refractory having small transverse passages extending therethrough for the relatively free flow of gas from the chamber 13 for burning at the outer face of the plate. At present, silicon-carbide is the material commonly used. Suitable silicon-carbide plates are sold by the Carborundum Company under the designation A42A-46. Preferably, a screen 22 of heat resistant metal covers and is spaced a short distance outwardly from the face of the plate, the screen having a back-turned flange 23 telescoped around the periphery of the casing 12 and suitably secured thereto.

Usually, the casing 12 is composed of cast iron which possesses a coeflicient of thermal expansion substantially higher than that of the face plates 11, that of siliconcarbide being near zero. Also, only the outer face of the plate attains a high temperature, that of the back surface 24 being not materially higher than that attained by the cast iron of the casing 12. Under these conditions, a given rise in the temperature ofthe burner head will cause edgewise expansion of the casing 12 substantially greater than that of the face plate 11.

In accordance with the present invention, a gasket ring 26 is interposed between the shoulder 21 and the back 24 of the supported plate 11 and composed of material which will accommodate the temperature changes and differential expansion above referred to while maintaining a gas-tight seal around the plate under all conditions of service use. Suitable for this purpose is a flexible ceramic fiber paper fitted or formed by felting, as on an ordinary paper making machine and composed of a combination of metallic oxides, for example aluminum and silicon. Of the papers of this type now available and having the desired properties is one sold by the Carborundum Company under the trade name of Fiberfrax 970-], recommended for continuous use at 2300 deg. F. and possesses a density when uncompressed of about 12 lbs. per cu. ft.

The paper ring 26 is about an eighth of an inch thick and one side is bonded to the cast iron surface of the shoulder 21 by sodium silicate cement. The opposite side is bonded to the silicon-carbide surface by a suitable cement such as one sold by the Carborundum Company and designated QF-180.

In another aspect, the invention contemplates holding of each plate against the gasket ring 26 by contouring the wall 20 of the flange 19 to form with the opposed edge 27 of the plate 11 a narrow space of wedge-shaped cross-section and filling this space with a high temperature refractory cement which hardens into a rigid ring 28. Of the cements now available and suitable for this purpose is Sauereisen No. 63 which bonds quite securely to the cast iron wall 20 and interlocks in the pores in the opposed edge 27 of the silicon-carbide plate and becomes permanently secured to the latter.

Herein, the wall 20 is frusto-conical and diverges inwardly toward the shoulder 21 making an included angle of about ten degrees with the plate edge 27. The wall thus overlies the wedge-shaped filling 28 and holds the latter and the face plate 11 in the casting recess under all conditions encountered in service use. Thus, even if the cast iron surface 20 breaks away from the filling 28 due to the greater edgewise expansion of the casing 12 as above described, the gasket ring 26 yields and accommodates the relative edgewise shifting between the shoulder 21 and the back 24 of the face plate while always maintaining a gastight seal around the full periphery of the face plate.

To reduce the relative edgewise expansion between the silicon-carbide face of the burner and its enclosing flange, carbide is divided lengthwise into the two separate plates 11 above referred to. For this purpose, the face plates are arranged end to end with their adjacent ends backed by end portions 26a of the gasket rings above described seated on shoulders 21a on bar 30 integral with the casing 12 and extending crosswise across the open end of the casing.

We claim as our invention:

1. A gas burner having, incombination, a dished casing having an opening at one side defined by an axiatly facing shoulder surrounded by a continuous peripheral flange having an internal wall converging outwardly and away from said shoulder, a burner plate received in the recess defined by said shoulder and flange wall and having transverse passages for passing therethrough gas delivered under presure into said casing for burning at the outer face of the plate, said casing being composed of material having a coefficient of thermal expansion substantially greater than the material of said plate, a gasket ring covering said shoulder and cemented on one side to the shoulder and on the other side to the back of said plate, and a refractory filling disposed in the space between said flange wall and the peripheral edge of said plate and bonded to said wall and the edge surface of the plate, said gasket ring being composed of ceramic fiber paper adapted to accommodate the relative edgewise shifting of said plate and shoulder incident to temperature changes whereby to seal the joint between the casing and plate against the escape of gas therethrough under the changing temperature conditions occurring in service use of the burner.

2. A gas burner having, in combination, a dished casing having an opening at one side defined by an axially facing shoulder surrounded by a continuous peripheral flange, a burner plate received in the recess defined by said shoulder and flange wall and having transverse passages for passing therethrough gas delivered under pressure into said casing for burning at the outer face of the plate, said casing being composed of material having a coeflicient of thermal expansion substantially greater than that of said plate, a gasket ring covering said shoulder and cemented on one side to the shoulder and on the other side to the back of said plate, and filling of high temperature refractory cement disposed in the space between said flange wall and the peripheral edge of said plate and bonded to said wall and the edge surface of the plate, said gasket ring being composed of ceramic fiber paper adapted to accommodate the relative edgewise shifting of said plate and shoulder incident to temperature changes whereby to seal the joint between the casing and plate against the escape of gas therethrough under the changing temperature condition occurring in service use of the burner.

3. A gas burner as defined in claim 2 in which said gasket is a paper of refractory material of sufficient thickness to maintain a gas-tight seal around the plate.

References Cited UNITED STATES PATENTS 1,223,308 4/1917 Bone et a1 15899 1,983,863 12/1934 Mantz 158115 3,107,720 10/1963 Swinderin 158-116 3,114,363 12/ 1963 Koltlln 1264l 3,199,570 8/1965 Williams 158-104 3,251,356 5/1966 Prince et a1. l5899 XR FOREIGN PATENTS 1,168,747 9/ 1958 France.

821,429 10/1959 Great Britain.

FREDERICK L. MATTESON, IR., Primary Examiner.

H. B. RAMEY, Assistant Examiner. 

2. A GAS BURNER HAVING, IN COMBINATION, A DISHED CASING HAVING AN OPENING AT ONE SIDE DEFINED BY AN AXIALLY FACING SHOULDER SURROUNDED BY A CONTINUOUS PERIPHERAL FLANGE, A BURNER PLATE RECEIVED IN THE RECESS DEFINED BY SAID SHOULDER AND FLANGE WALL AND HAVING TRANSVERSE PASSAGES FOR PASSING THERETHROUGH GAS DELIVERED UNDER PRESSURE INTO SAID CASING FOR BURNING AT THE OTHER FACE OF THE PLATE, SAID CASING BEING COMPOSED OF MATERIAL HAVING A COEFFICIENT OF THERMAL EXPANSION SUBSTANTIALLY GREATER THAN THAT OF SAID PLAE, A GASKET RING COVERING SAID SHOULDER AND CEMENTED ON ONE SIDE TO THE SHOULDER AND ON THE OTHER SIDE TO THE BACK OF SAID PLATE, AND FILLING OF HIGH TEMPERATURE REFRACTORY CEMENT DISPOSED IN THE SPACE BETWEEN SAID FLANGE WALL AND THE PERIPHERAL EDGE OF SAID PLATE AND BONDED TO SAID WALL AND THE EDGE SURFACE OF THE PLATE, SAID GASKET RING BEING COMPOSED OF CERAMIC FIBER PAPER ADAPTED TO ACCOMMODATE THE RELATIVE EDGEWISE SHIFTING OF SAID PLATE AND SHOULDER INCIDENT TO TEMPERATURE CHANGES WHEREBY TO SEAL THE JOINT BETWEEN THE CASING AND PLATE AGAINST THE ESCAPE OF GAS THERETHROUGH UNDER THE CHANGING TEMPERATURE CONDITION OCCURRING IN SERVICE USE OF THE BURNER. 